Our Dazzling Night Sky When the Milky Way Collides with Andromeda in 4B Years
kottke.org
kottke.org
From a logarithmic standpoint, around 1 billion years is when geologically interesting things happen to the earth as it's no longer to sustain life an have the oceans boil over as well.
I love how Wikipedia likes to cite things like this.
https://astronomy.stackexchange.com/questions/5914/is-it-pos...
https://worldbuilding.stackexchange.com/questions/44910/how-...
/s I mean it apparently is so bad they sent time travelers back in time to try and fix it. (Google: John Titor)
There's a wonderful Wiki-dive on these topics too:
Though yes, they're already non-identical. Some correspondence might tend to continue, whether it's humans or other intelligence applying it.
And yes, ultimately, definitions matter and tend to define arguments.
It is also interesting to think about two galactic civilizations coming together over a common need to survive in the post collision Milkdromeda galaxy.
> it’s extremely unlikely that any individual stars will collide because of the sheer amount of empty space in galaxies.
If Earth gets wiped out by a meteor, or weaponized Ebola, in either case it might be nice to have a backup.
The US, currently the greatest military power in history, can't currently even justify a Vietnam-scale conflict, much less a WWII-scale one. Improvements in agriculture have radically reduced food as a resource war motivator, and I think that in a few decades, renewables will have wiped out energy as a resource war motivator as well.
Ideology without serious contention doesn't lead to war, it leads to taunting remarks on the internet.
In 1913, "less than a year before the Great War broke out, the Economist reassured its readers with an editorial titled “War Becomes Impossible in Civilized World.”
“The powerful bonds of commercial interest between ourselves and Germany,” the Economist insisted, “have been immensely strengthened in recent years … removing Germany from the list of our possible foes.”"
http://blogs.reuters.com/anatole-kaletsky/2014/06/27/world-w...
> can't currently even justify a Vietnam-scale conflict, much less a WWII-scale one.
https://www.cnbc.com/2019/01/24/doomsday-clock-risk-of-globa...
"Doomsday Clock timekeepers say risk of global annihilation remains at Cold War highs"
The only reason for that is the misguided decision to include some fuzzy-headed interpretation of catastrophic, anthropogenic global warming (CAGW) in the risk of "doomsday".
The risk of actual nuclear war is far lower today than it was during the Cold War. The risk of an individual nuclear weapon going off in a city is much higher, however.
Please explain why do you think that the systems that are automatically triggered by the nuclear weapon going off in a city would not do what they are designed to do: all respond to the perceived attack with their full power.
Also explain how the humans trained to start the retaliation sequence would all not do what they are trained to do, once a city where their families are gets destroyed.
The "doomsday machines" are real.
Service jobs won't be needed, but we as a civilization can't just sit idle. We still need fulfillment so whether there's money or not at that point we need to encourage future fulfillment else we die out from sheer boredom.
I like to hope we move past all our petty differences, embrace the humanity that we are one single species. Then we drop the super stars, celebrity adoration, and desire to be uber wealthy and 'control' other people and we can focus more on arts and sciences. Arts for people to enjoy life, sciences for people to explore what's out there.
Imagine if the only careers were in entertainment and science/research what we could accomplish and imagine if everyone had equal footing to go into their chosen path. If we had 10x the scientists or 100x the scientists working on global problems and even intergalactic ones. We might actually make it to the stars.
But before we get there --there will be unrest and wars, just more middle class vs elites. Also potential wars for water as it becomes more scarce if we don't fix global warming soon.
I dream of a day when wage labor is looked back on as almost as oppressive and horrible as chattel slavery. We're a long way from that, though. The technology is almost here, but the political will is not.
The trick, then, is fulfillment. How do we give our lives meaning, if not through our labor? And how do we fight the brutal addictions of social media and passive consumption in order to achieve individual meaning? I fear a future where we don't have to work, but rather spend all our time sharing memes about how lonely and depressed we are.
You could drop most of Western Europe into central western Canada, and we literally wouldn’t notice.
> Calhoun's work with rats inspired the 1971 children's book, Mrs. Frisby and the Rats of NIMH, by Robert C. O'Brien, which was adapted into a 1982 animated film, The Secret of NIMH.
Calhoun did his work on rats/mice at the National Institute of Mental Health (NIMH).
So my thought process was: have their scientists realized that the Milky Way is going to collide with them in 4B years? Are they already sharing pictures of what it will look like?
[1] That is, when the hot gas cooled down enough to convert from free electrons and protons (and some helium nucleii) that scatter photons into neutral atoms that don't.
Other factors make the infinitely old part unlikely, though.
https://en.wikipedia.org/wiki/Olbers%27_paradox
Most photons emitted from within our solar system are liable to collide with dust or gas eventually, most likely in the interstellar medium of our galaxy. Only a tiny fraction will collide with stars in our galaxy. The rest of our galaxy cluster covers a small solid angle of the skies of any of the bodies in our solar system. Finally, the small minority of photons that escape our galaxy cluster without being absorbed are most likely to stretch to arbitrarily long wavelengths and vanish from practical physical detectability well before the infinite future. It is vanishingly unlikely for an individual photon to couple to a lightlike geodesic that intersects a star at more than a few billion light-years.
For experts, there is some meat in §§1-2 of these lecture notes: http://www.tapir.caltech.edu/~chirata/ph217/lec02.pdf
Source: my favorite Wikipedia page, https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future
https://www.space.com/42901-milky-way-galaxy-large-magellani...
Cool images though
https://www.google.com/url?q=https://www.universetoday.com/1...
Or, something few consider, they might have plateaud way earlier, after most low hanging fruits have been achieved (fire, steam engine, electricity, nuclear power, computing, telecommunications) and the rest are diminishing returns...
"Limited by the laws of physicals" implies only physical laws are the limitation.
Whereas my response was more about being more limited (due to complexity, lack of resources, etc). So response was about a possible way lower envelope. I.e. not necessarily much more advanced than we are today, with diminishing advances in various areas.
So no "worldwide climate engineering" (except the clumsy stuff we already have), and no personal robot assistance of sci-fi style...
The surface brightness of Andromeda and the Milky Way are both around 22 mag/arcsec2. As andromeda grows closer, the surface areas spreads out in our sky, so even as it gets closer it’s not really going to get brighter.
I think what we're looking at right now is making life a little more uncomfortable and expensive for part of humanity. That's as bad as we can manage right now. The fact that we treat it like the end of the world says more about us than the damage itself does.
You are talking about global warming and the like, right? There's another possibility, and it involves nuclear weapons. THOSE can sterilize the planet many times over.
Example: https://www.tandfonline.com/doi/abs/10.1080/01490451.2019.16...
[0] https://en.wikipedia.org/wiki/Nuclear_holocaust#Likelihood_o...
What do you mean they'll pass through each other.
One of my favorite factoids: if you fire a laser from the surface of the earth (and the beam magically stayed perfectly straight), you have a small but significant chance of hitting the sun or the moon, but anything beyond that, the scale is so enormous, the odds that your laser would ever hit a celestial body anywhere in the universe are effectively zero.
There are many youtube videos that try to visualize the incomprehensible scale of space. Here is one just for our solar system https://www.youtube.com/watch?v=dCSIXLIzhzk
Think of two clouds of gas colliding. The clouds as a whole collide, yes, but there's no molecular fusion happening. The molecules themselves don't collide.
"Pass through each other" is not the clearest wording.
It was not, mea culpa. :D
The Englese, she is the very hard language to speak.
Stars can only get so massive, but black holes can get much much more massive.
But even with supermassive black holes, it doesn’t change the odds of colliding solar systems that much.
There is just way too much space in between to matter.
> no difference ... gravitationally.
"practically no difference ... gravitationally, provided one is at a very large distance compared to the outer surface of an astrophysical black hole." would be more accurate.
Up close to a real black hole additional shear and tension becomes obvious, although you will generally be in the region that would be close to the surface of a star of comparable mass.
Astrophysical black holes are more complicated objects than the theoretical Vaidya-Bonnor-Kerr (VBK) black holes, especially when they are not isolated. VBK black holes absorb radiation and emit Hawking radiation (V part), including self-interacting matter (B part, although that is mostly dealing with classical electromagnetism), and they also rotate (K part). VBK breaks several symmetries: the exterior spacetime is not static, not stationary, and spherical symmetry goes to axial symmetry, including all the incoming and outgoing radiation. Real rotating black holes would break axial symmetry because real matter tends to clump (in particular theoretical VBK exterior matter does not look like accretion discs).
Small perturbations of the axial symmetry of VBK black holes tend to cause black holes to spin up as matter falls onto them. There is observational support to suggest that most real black holes are likely spinning extremely rapidly. The Kerr vacuum around a VBK is equipped with regions in which objects are dragged around in the direction of the VBK black hole's rotation. As the original angular momentum of the star may be increased by infalling material, a real black hole likely has a strong region extending well outside of where the surface of a star of comparable mass would be. While the dragging effect falls off quickly with distance outside the outermost surface of the outermost of these regions, if we replaced the sun with a real black hole which rotates at extremely high rates, all eight planets' orbits would precess compared to their orbits around the sun. Given enough observation time, this would be especially noticeable for objects on high-inclination, low-ellipticity orbits, even if they are near the outer edge of the Oort cloud. Reducing the angular momentum dramatically increases the observation time needed to distinguish gravitationally between a (growing!) solar-mass black hole and a (shrinking!) solar-mass star.
Beyond the Oort cloud things aren't gravitationally bound to our solar system anyway, so by the time you're a couple hundred thousand astronomical units away, you are on safe territory with practical gravitational indistinguishability.
In terms of light and radiation, though, swapping the sun for a solar-mass black hole would be pretty noticeable, for example https://en.wikipedia.org/wiki/Poynting%E2%80%93Robertson_eff... or https://en.wikipedia.org/wiki/Yarkovsky_effect
despite the galactic collision and the dazzling view from Earth, it’s extremely unlikely that any individual stars will collide because of the sheer amount of empty space in galaxies.
I don't think it's likely anything would be close enough to change earth's orbit and not the sun's
I'm sure there are far too many variables to predict with any accuracy, but curious if a better space nerd than I has any guess as to the likelihood of such an event.